The birth of four pups to first-time parents Valkyrie and Ziggy earlier this year marks the first documented river-otter births in Woodland Park Zoo’s nearly 120-year history.

In a blog posted on its website, the zoo said the two female and two male pups together weighed “almost as much as one coconut.”

The tiny, fuzzy pups were born blind. They’ll rely on their mother, Valkyrie, for care through their first year.

“At just weeks old, the pups are busy nursing and curling up into adorable otter balls while they sleep,” the zoo said in its blog. “The first year is crucial for otter pups. Because Valkyrie is a first-time mother, we want to be sure she’s providing appropriate care for each pup. We’re happy to report each pup has a full belly, a good sign they’re nursing. She’s being a good mom and providing attentive maternal care.”